The Commissioner of Labor for Oklahoma, Mark Costello, was killed in a stabbing at a fast food restaurant in Oklahoma City on Sunday, local broadcasters reported, citing unnamed sources. Police declined to confirm that Costello was the victim but said one family member stabbed another family member at least four times with a knife after the pair agreed to meet at the restaurant following a fight earlier in the day. "So sorry to hear the tragic news about Mark Costello," Oklahoma City Mayor Mick Cornett said in a Tweet. Local broadcaster News 9, citing unnamed sources, reported that Costello was...